Saja Boys’ ‘Soda Pop’ was once a guitar demo gathering dust. Now, it’s a success story for songwriter Vince.

An old guitar demo recorded at least seven years ago became the foundation for the “KPop Demon Hunters” track “Soda Pop,” a Billboard-charting song performed in the film by fictional boy band Saja Boys, said songwriter Vince.

“It was literally just a guitar sketch that I did in my own room seven or eight years ago. Then one day, a colleague and producer named 24 asked for something bright, so I handed this demo over to him under the title ‘Ice Cream,’ which he reworked and became Saja Boys’ ‘Soda Pop,'” said Vince in a recent interview with the local press. He also composed Saja Boys’ “Your Idol.”

“Not a lot from my demo was reflected in the final song but the intro part of ‘Soda Pop,’ which says ‘Don’t want you, need you, yeah, I need you to fill me up’ originated from the my demo’s chords.”

“Soda Pop” ranked No. 14 and “Your Idol” on No. 8 on the Billboard Hot 100 as of August 17, a few spots behind “Golden” at No. 1.

Vince, an NYU graduate, is a veteran producer under The Black Label, home to artists like Allday Project and Jeon Somi. His credits include Big Bang’s “Still Life” (2022), G-Dragon’s “Super Star” (2018), Jennie’s “You & Me” (2023), Lisa’s “Money” (2021), Jeon Somi’s “Fast Forward” (2023) and the list goes on.

The producer says that working on the animation’s soundtracks was pretty much similar to working with real artists — except for one thing.

“When working with an artist, I can actively make suggestions to make this song sound and look better. But for this project, I had to align with the film. We got a lot of feedback from Sony and made a lot of adjustments from the initial demo,” he said.

“A lot of the things Sony emphasized was that ‘Soda Pop’ is a song that has be really bright. They said to explicitly make it brighter. Also for the lyrics as well — they told us to make them bubblier.”

He worked on the project, relying on 2-D sketches of Saja Boys and the relevant scenes.

“When I saw the end result, honestly, I was really surprised at how good the quality of it was,” he said.

But producing isn’t all he does. He also takes the stage with his own songs, coming back with his own digital single “Cha Cha Cha” nearly two years after his debut EP “The Drive” (2023).

“Cha Cha Cha” is an easy-listening summer track that samples well-known Korean trot singer Seol Un-do’s “Cha Cha Cha Together” (1991), with a little bit of a hip-hop and Latin twsit. The song also features G-Dragon.

“Around the time G-Dragon was discharged from the army [2019], he came by our studio and listened to the demo of ‘Cha Cha Cha.’ Then he turned to me and asked, ‘Vince, do you want to be a star?’ and I said, ‘Yes! Yes I want to become a star!’ And just like that, he agreed to feature in this song,” he said.

“He changed around some lyrics and gave me some ideas, which I absolutely, 100 percent, accepted.”

Having been in the K-pop industry — one that has undergone seismic changes — for more than a decade, his mindset toward making music has evolved as well.

“Just a few years ago, I held pop artists and producers in such high regard, wondering, ‘What do I have to do to become like them?’ Now, with many of those I admire reaching out to me first, I’ve come to see them as fellow musicians. That shift has broadened my perspective on music as well,” he said.

“After ‘KPop Demon Hunters’ became such a hit, a lot of producers and artists that I have admired messaged me, suggesting we work together.”

In regard to the rumored sequel of “KPop Demon Hunters,” Vince said, “If it gets made, it would be really nice if our team gets to make the music again.”

Vince’s “Cha Cha Cha” will be released on August 18 at 6 p.m.

BY JIN EUN-SOO [jin.eunsoo@joongang.co.kr]